Motion capture technology involves recording human movements and translating them onto digital models. There are several types of motion capture techniques, including optical, mechanical, and magnetic. Optical motion capture uses multiple cameras to track passive or active markers placed on an actor's body. Early motion capture systems involved tracing live-action footage frame-by-frame (rotoscoping). Modern optical systems can capture high-resolution movement data at fast frame rates.

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CHAPTER 1
INTRODUCTION TO MOTION CAPTURE TECHNOLOGY
"Motion Capture" is the term used to describe the process of recording
human movement and translating that movement onto a digital model. It is used in
military, entertainment, sports, medical applications for validation of computer
vision and robotics. In film making it refers to recording the actions of human
actors, and using that information to animate digital character models in 2D or 3D
computer animation. When it includes face, fingers and captures subtle
expressions, it is often referred to as performance capture in motion capture
sessions.
Movements of one or more actors are sampled many times per second,
although with most techniques motion capture records only the movement of
actors , not his or her visual appearance this animation data is mapped to a 3D
model so that the model performs the same actions as the actor. This is
comparable to the older technique of rotoscope such as 1978 "The Lord Of Rings"
animated film where visual appearance of the motion of an actor was filmed, then
the film is used as guide for the frame by frame motion of the hand-drawn
animated character.
Camera movements can also be motion captured so that a virtual camera in
the scene will pan, tilt, or dolly around the stage driven by a camera operator while
the actor is performing, and the motion capture system can capture the camera and
props as well as the actor's performance. This allows the computer-generated
characters, images and sets to have the same perspective as the video images from
the camera. A computer processes the data and displays the movements of the
actor, providing the desired camera positions in terms of objects in the set.
Retroactively obtaining camera movement data from the captured footage is
known as match moving or camera tracking.

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Research and development of digital MOCAP technology started in pursuit
of medical and military applications in the 1970s. The CGI industry discovered the
technology‟s potentials in the 1980s. Since some of this book‟s readers weren‟t
born in the 1980s, let‟s recall the 1980s. In the 1980s there were floppy disks that
were actually floppy and most computers were equipped with monochrome
monitors, some with calligraphic displays. To view color images, for example
rendered animation frames, images had to be sent to a “frame buffer,” which was
often shared by multiple users due to its cost. Large computers were housed in ice
cold server rooms. The noise of dot matrix printers filled offices. Ray-tracing and
radio city algorithms were published in the 1980s. Renderers based on these
algorithms required a supercomputer or workstations to render animation frames
in a reasonable amount of time. Personal computers weren‟t powerful enough.
(Ray-tracing and radio city didn‟t become widely available until the computing
power improved.) CPUs, memories, storage devices, and applications were more
expensive than today. Wave front Technologies developed and marketed the first
commercial off-the-shelf 3D computer animation software in 1985. Only a handful
of computer animation production companies existed. Most of the animations that
they produced were “flying logos” for TV commercials or TV programme‟s
opening sequences. These were often 15 to 30 seconds long per piece. The readers
who saw “Brilliance” (also called “Sexy Robot”) in the 1980s probably still
remember the astonishment of seeing a computer generated character, a shiny
female robot, moving like a real human being.
“Brilliance” was produced by Robert Abel and Associates for the National
Canned Food Information Council and was aired during the 1985 Super Bowl.
They invented their own method for capturing motion for the project. They
painted black dots on 18 joints of a female model and photographed her action on
a swivel stool from multiple angles. The images were imported into Silicon
Graphics workstations and a number of applications were employed to extract the

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information necessary to animate the CGI robot. They didn‟t have enough
computing power to render frames for the 30 second piece in house. So, in the
final 2 weeks before the project deadline they borrowed VAX 11/750 computers
around the country to render. The final product was a ground breaking piece and is
regarded as a milestone in the history of CGI.

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CHAPTER 2
HISTORY OF MOTION CAPTURE
The use of motion capture to animate characters on computers is relatively
recent, it started in the 1970‟s and now just beginning to spread . Motion Capture
is recording the movements of human body for immediate analysis. The captured
information can be as simple as catching the body position in space or as forms
like bvh, bip, fbx etc. Which can be used to animate 3D characters in 3D„s max,
maya etc. Motion capture for animation is the superposition of human movement
on their virtual identities this capture can e direct such as the animation of virtual
function of movement of an arm or indirect such as that of human hand with a
more thorough as the effect of light color. To make the most convincing human
movement in “snow white”, Disney studios design an animation film on a film or
real players.
2.1 ROTOSCOPING
A Rotoscoping is a device that enables animators to trace live action
movement, frame by frame, for use in animation. This method is called
"Rotoscoping".
Fig 2.1 Rotoscoping

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2.1.1Captured Video
Rotoscoping works by first capturing a video of a real actor around props
that resembles elements of a scene.
Fig 2.2 Capturing a video
2.1.2Tracing
Animators then trace over each frame of the recorded video, this would
result in a figure that moved in a very realistic fashion.
2.1.3Post Processing:
Finally, the animated figure would be colored and then integrated with
various background layers to create the final shot.
Fig 2.3 Post Processing

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CHAPTER 3
DIFFERENT TYPES OF MOTION CAPTURE
Motion Capture technology can be achieved by using the following three
types of techniques:
1.Mechanical motion capture
2.Optical motion capture
3.Magnetic motion capture
Now although this technique is effective, it still contains some problems
(weight, Cost).
But against any doubt that the motion capture will become one of the basic
tools of animation.
3.1Mechanical Motion capture:
This technique of motion capture is achieved through the use of an
exoskeleton. Each joint is then connected to an angular encoder. The value of
movement of each encoder (rotation etc...) is recorded by a computer that by
knowing the relative position encoders (and therefore joints) can rebuild these
movements on the screen using software. An offset is applied to each encoder.
because it is very difficult to match exactly their position with that of the real
relationship (and especially in the case of human movements).

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Fig 3.1 Mechanical Motion Capture using Exo skeleton
3.1.1 Advantages and Disadvantages
1.This technique offers high precision and it has the advantage of not being
influenced by external factors (such as quality or the number of cameras for Optical
MOCAP).
2.But the catch is limited by mechanical constraints related to the implementation
of the encoders and the exoskeleton. It should be noted that the exoskeleton
generally use wired connections to connect the encoders to the computer. For
example, there is much more difficult to move with a fairly heavy exoskeleton and
connected to a large number of simple son with small reflective sphere. The
freedom of movement is rather limited.
3.The accuracy of reproduction of the movement depends on the position encoders
and modeling of the skeleton. It must match the size of the exoskeleton at each
morphology. The big disadvantage comes from the coders themselves because if
they are of great precision between them it cannot move the object to capture in a so
true. In effect, then use the method of optical positioning to place the animation in a
decor. Finally, each object to animate to need an exoskeleton over it is quite
complicated to measure the interaction of several exoskeleton. Thereby bringing
about a scene involving several people will be very difficult to implement.

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3.2 Magnetic motion capture:
Magnetic motion capture is done through a field of electro-Magenta is
introduced in which sensors are coils of sensors electriques, Les son are
represented on a place mark in 3 axes x,y,z. To determine their position on the
capture field disturbance created by a son through an antenna then we can know its
orientation.
Fig 3.2 Magnetic Field Transmitter Source
3.2.1Advantages and disadvantages
1.The advantage of this method is that data captured is accurate and no further
calculations excluding from the calculation of position is useful in handling.
2.But any metal object disturbs the magnetic field and distorts the data.
3.3 Optical Motion Capture:
The capture is based on optical shooting several synchronized cameras, the
synthesis of coordinates (x, y) of the same object from different angles allows to
deduce the coordinates (x, y, z). This method involves the consideration of
complex problems such as optical parallax. distortion lens used, etc. The signal
thus undergoes many interpolations. However. a correct calibration of these
parameters will help in high accuracy of data collected. To determine their position
on the capture field disturbance created by a son through an antenna then we can
know its orientation.

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Fig 3.3 Camera emitting Infrared Radiations
The operating principle is similar to radar: the cameras emit radiation
usually infrared, reflected by the markers and then returned to the same cameras.
Checking the information of each camera (minimum two cameras ) to determine
the position of markers in virtual space.

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CHAPTER 4
METHODS AND SYSTEMS
Motion tracking or motion capture started as a photogrammetric analysis tool in
biomechanics research in the 1970s and 1980's and expanded into education. training.
sports and recently computer animation for television. cinema and video games as the
technology matured. A performer wears markers near each joint to identify the motion by
the positions or angles between the markers. Acoustic, inertial, LED, magnetic or
reflective markers or combinations of any of these are tracked . Optimally at least two
times the frequencyrate of the desired motion, to sub millimeter positions.
4.1 OPTICAL SYSTEMS:
Optical systems utilize data captured from image sensors to triangulate the 3D
position a subject between one or more cameras calibrated to provide overlapping
projections. Data acquisition is traditionally implemented using special markers attached
to an actor. However, more recent systems are able to generate accurate data by tracking
surface features identified dynamically for each partial. subject Tracking a large number
of performers or expanding the capture area is accomplished by the addition of more
cameras. These systems produce data with 3 degrees of freedom for each marker and
rotational information must be inferred from the relative orientation of three or more
markers for instance shoulder. elbow and wrist markers providing the angle of the elbow.
4.1.1 PASSIVE MARKERS
Fig 4.1 A dancer wearing a suit used in optical motion capture

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Passive optical system use markers coated with a retro reflective material
to reflect light back that is generated near the cameras lens. The camera's
threshold can be adjusted so only the bright reflective markers will be sampled,
ignoring skin and fabric.
The centroid of the marker is estimated as a position within the 2
dimensional image that is captured. The grayscale value of each pixel can be
used to provide sub-pixel accuracy by finding the centroidof the Gaussian.
Providing two calibrated cameras see a marker, a 3 dimensional fix can be
obtained. Typically a system will consist of around 6 to 24 cameras. Systems of
over three hundred cameras exist to try to reduce marker swap. Extra cameras
are required for full coverage around the capture subject and multiple subjects.
Vendors have constraint software to reduce problems from marker
swapping since all markers appear identical. Unlike active marker systems and
magnetic systems. passive systems do not require the user to wear wires or
electronic equipment. Instead. hundreds of rubber balls are attached with
reflective tape, which need to be replaced periodically. The markers are usually
attached directly to the skin (as in biomechanics) or they are velcroed to a
performer wearing a full body spandex/lycra suit designed specifically for
motion capture. This type of system can capture large numbers of markers at
frame rates as high as 2000fps. The frame rate for a given system is often
balanced between resolution and speed: a 4-megapixel system normally runs at
370 hertz but can reduce the resolution to 3 megapixels and then run at 2000
hertz. Typical systems are S100,000 for 4-megapixel 360-hertz systems. and
S50,000 for 3-megapixel 120- hertz systems.
4.1.2 Active Marker
Active optical systems triangulate positions by illuminating one LED at a
time very quickly or multiple LEDs with software to identify them by their
relative positions. somewhat akin to celestial navigation. Rather than reflecting

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light back that is generated externally, the markers themselves are powered to
emit their own light. Since Inverse Square law provides 1/4 the power at 2 times
the distance, this can increase the distances and volume for capture.
The TV series ("Stargate SG1") episode was produced using an active
optical system for the VFX. The actor had to walk around props that would
make motion capture difficult for other non-active optical systems.
ILM used active Markers in Van Helsing to allow capture of the Harpies on
very large sets. The power to each marker can be provided sequentially in phase
with the capture system providing a unique identification of each marker for a
given capture frame at a cost to the resultant frame rate. The ability to identify
each marker in this manner is useful in real time applications. The alternative
method of identifying markers is to do it algorithmically requiring extra
processing of the data.
Fig 4.2 Several markers are placed at specific position an actor's face during
facial optical motion capture
4.1.3 TIME MODULATED ACTIVE MARKER
Active marker systems can further be refined by strobing one marker on at
a time or tracking multiple markers over time and modulating the amplitude or
pulse width to provide marker ID. 12 megapixel spatial resolution modulated
systems show more subtle movements than 4 megapixel optical systems by

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having both higher spatial and temporal resolution.
Fig 4.3 Showing different stages of motion capture technology
Directors can see the actors performance in real time and watch the results
on the MOCAP driven CG character The unique marker reduce the turnaround by
eliminating marker swapping and providing much cleaner data than other
technologies. LEDs with onboard processing and a radio synchronization allow
motion capture outdoors in direct sunlight while capturing at 480 frames per
second due to a high speed electronic shutter. Computer processing of modulated
allows less hand cleanup or filtered results for lower operational costs. This
higher accuracy and resolution requires more processing than passive
technologies but the additional processing is done at the camera to improve
resolution via a sub pixel or centroid processing, providing both high resolution
and high speed. These motion capture systems are typically under $50,000 for an
eight camera megapixel spatial resolution 480 hertz system with one actor.
IR sensors can compute their location when lit by mobile multi-LED
emitters, e.g. in a moving car. With Id per marker, these sensor tags can be worn
underclothing and tracked at 500 Hz in broad daylight.

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4.1.4 SEMI-PASSIVE IMPERCEPTIBLE MARKER
One can reverse the traditional approach based on high speed cameras.
Systems use inexpensive multi-LED high speed projectors. The specially built
multi-LED IR projectors optically encode the space. Instead of retro-reflective or
active light emitting diode (LED) markers. the system uses photosensitive
marker tags to decode the optical signals. By attaching tags with photo sensors to
scene points the tags can compute not only their own locations of each point, but
also their own orientation, incident, illumination and reflectance.
These tracking tags that work in natural lighting conditions and can be
imperceptibly embedded in attire or other object & the system supports an
unlimited number of tags in a scene. With each tag uniquely identified to
eliminate marker reacquisition issues. Since the system eliminates a high speed
camera and the corresponding high-speed image stream, it requires significantly
lower data bandwidth. The tags also provide incident illumination data which can
be used to match scene lighting when inserting synthetic elements. The technique
appears ideal for on-set motion capture or real- time broadcasting of virtual sets
but has yet to be proven.
4.1.5 MARKER LESS
Emerging techniques and research in computer vision are leading to the
rapid development of the marker less approach to motion capture. Marker less
systems such as those developed at Stanford University of Maryland, MIT and
Max Plan Institute do not require subjects to wear special equipment for tracking.
4.2 NON OPTICAL SYSTEMS
An optical tracking system typically consists of 3 subsystems. The optical
imaging system, the mechanical tracking platform and the tracking computer.
The optical imaging system is responsible for converting the light from the
target area into digital image that the tracking computer can process. Depending

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on the design of the optical tracking system, the optical imaging system can vary
from as simple as a standard digital camera to as specialized as an astronomical
telescope on the top of a mountain. The specification of the optical imaging
system determines the upper-limit of the effective range of the tracking system.
The mechanical tracking platform holds the optical imaging system and is
responsible for manipulating the optical imaging system in such a way that it
always points to the target being tracked. The dynamics of the mechanical tracking
platform combined with the optical imaging system determines the tracking
system's ability to keep the lock on a target that changes speed rapidly.
The tracking computer is responsible for capturing the images from the
optical imaging system, analyzing the image to extract target position and
controlling the mechanical tracking platform to follow the target. There are several
challenges. First the tracking computer has to be able to capture the image at a
relatively high frame rate. This posts a requirement on the bandwidth of the image
capturing hardware. The second challenge is that the image processing software
has to be able to extract the target image from its background and calculate its
position. Several textbooks, image processing algorithms are designed for this task
but each has its own limitations. This problem can be simplified if the tracking
system can expect certain characteristics that is common in all the targets it will
track. The next problem down the line is to control the tracking platform to follow
the target. This is a typical control system design problem rather than a challenge,
which involves modeling the system dynamics and designing controllers to control
it. This will however become a challenge if the tracking platform the system has to
work with is not designed for real-time and highly dynamic applications, in which
case the tracking software has to compensate for the mechanical and software
imperfections of the tracking platform.

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Traditionally optical tracking systems often involves highly customized
optical and electrical subsystems. The software that runs such systems are also
customized for the corresponding hardware components. Because of the real-time
nature of the application and the limited size of the market, commercializing
optical tracking software posts a big challenge. One example of such software is
Optic Tracker, which controls computerized telescopes to track moving objects at
great distances, such as planes and satellites.
4.2.1 MAGNETIC SYSTEMS
Magnetic systems calculate position and orientation by the relative magnetic flux
of three orthogonal coils on both the transmitter and each receiver. The relative intensity of
the voltage or current of the three coils allows these systems to calculate both range and
orientation by meticulously mapping the tracking volume. The sensor output is 6D0F,
which provides useful results obtained with two-thirds the number of markers required in
optical systems; one on upper arm and one on lower arm for elbow position and angle.
The markers are not occluded by nonmetallic objects but are susceptible to magnetic and
electrical interference from metal objects in the environmental like rebar (steel
reinforcing bars in concrete) or wiring which affect the magnetic field and electrical
sources such as monitors, lights, cables and computers. The sensor response is nonlinear,
especially toward edges of the capture area. The wiring from the sensors tends to
preclude extreme performance movement. The capture volumes for magnetic systems are
dramatically smaller than they are for optical systems. With the magnetic systems, there is
a distinction between “AC" and DC' systems: one uses square pulses, the other uses sine
wave pulse.

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CHAPTER 5
APPLICATIONS
5.1.Entertainment
1.Computer generated characters in live action films like avatar, polar
express.
2.Games using motion capture technology such as prince of persia, grand
theft auto 5 etc.
5.2.Medicine
1.For gait analysis, rehabilitation.
2. Injury prevention, performance analysis, performance enhancement in
sports.
5.3Science / Engineering
1.In Engineering for Biped robot developments.
2. In Military for field exercises, virtual instructors and role-playing games.

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CHAPTER 6
ADVANTAGES
Motion capture offers several advantages over traditional computer
animation of a 3D model
1.More rapid, even real time results can be obtained. In entertainment
applications this can reduce the costs of key frame-based animation.
2.The amount of work does not vary with the complexity or length of the
performance to the same degree as when using traditional techniques. This allows
many tests to be done with different styles or deliveries.
3.Comlpex movement and realistic physical interactions such as secondary
motions, weight and exchange of forces can be easily recreated in a physically
accurate manner.
4.The amount of animation data that can be produced within a given time is
extremely large when compared to traditional animation techniques. This
contributes to both cost effectiveness and meeting production deadlines.
5.Potential free software and third party solutions reducing its costs.

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CONCLUSION
Although the motion capture requires some technical means, we can quite
get what to do it yourself at home in a reasonable cost that can make your own
short film.
Motion capture is a major in the field of cinemas as you can reprocess the
image in a more simple in fact it is easier to modify an image captured a classic
scene, all although this is too expensive, but it is also a major asset in medicine,
for example it can be used to measure the benefit of a transaction via recording of
the movement of patient before or after the operation (such as in the case of
application prosthesis or simply at a medical classic in the future perhaps).

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REFERENCES
1.Goal, W.; Palmer, C. (2013). "Temporal Control and Hand Movement
Efficiency in Skilled Music Performance".
2.Jon Rudolf, Anatomy of an MMORPG,
http://radoff.com/blog/2008/08/22/anatomy-of-an-mmorpg/
3."Jaguar Explorer Val #1 Issue #2". January 20, 1998. Retrieved 2012-12-01.
4.http://www.newsweek.com/video/2007/03/06/videogames-organic-motion.html
5.Larry Greene Meier. "E-Motion: Next-Gen Simulators to Blur the Line between
Person and Avatar".